Combined insulating bushing and transformer



G. E. JANSSON 1,868,606

COMBINED INSULATING BUSHING AND TRANSFORMER .Filed Dec. l, 1930 2Sheets-Sheet l July 26, 1932.

7 L u, W 4 s m Wm July26, 1932. G. E. JANSSON COMBINED INSULATINGBUSHING AND TRANSFORMER Filed Deo. 1, 1950 2 Sheets-Sheet Patented July26, 1932` UNITED 'sT-Aras PATENT OFFICE n A. f l. GUSTAV E. JANSSON, FATLANTIC, MASSACHUSETTS, ASSIGNORTO CONDIT ELECTRICAL MANUFACTURINGCORPORATION, OF

Tron or MASSACHUSETTS SOUTH BOSTON, MASSACHUSETTS, A CORPORA- coMBINEDmsULAriNG Busnme AND TRANSFORMER Application' mea- Decanteri 1, 1936.serial mi 499,143.

This invention relates to high tension 'insulating bushings having meansby whlch power at low potential can be derived from A the potentialofthe line connected with the high voltage terminal of the bushing forthe operation of relays, measuring devices, synchronizing indicators andthe like.

Heretofore small amounts of low voltage power have been obtained from ahigh tension insulating bushing by utilizing the electrostatic capacitybetween selected conducting parts of the bushing. The amount of power,however, -that is obtained in this way is wholly inadequate to performall the operations desired and for which an electromagnetic transformeras a separate apparatus is now required. l

It is an object of the present invention to provide a novelconstructionfor an insulating bushing having means by which an abundance of lowtension power can be derived from the high tension line which is\connected to the bushing. In carrying out lthis object of the inventionthe voltagedrop between the hightension terminal and the groundv iangeof the bushing is divided between a plurality of reactance unit and theprimary winding of an electromagnetic transformer all of which areconnected in series and are included in the insulating enclosing shellof the bushing. This arrangement permits the use of a relatively lowvoltage transformer, the insulation of which presents no particulardiiiiculty.

A further object of provision of a voltage transformer, suitable to beincorporated in a high tension insulatinsulating bushings havingauxiliary low.

potential terminals.^

Fig. 1' is an elevation partly in section of a i high tension insulatingbushingv embodying the invention.

Fig. 2 is a section taken on line 2-2 of Fig. 1.

the invention the` Fig. 3 is a diagrammatic view of thepotentialtransforming elements of Fig. 1.

Fig. 4 is a sectional detail of a modified construction of reactorunits.

Fig. 5 is an elevation partly in section of a potential transformerconstructed in accord?. ance with the invention.,v

Fig. 6 is a section along line 6-6 of Fig. 5;

Fig. 7 is a diagrammatic view illustrating the potential transformingelements of Fig. 5. As shown in Fig. 1 of the drawings the potentialtransforming device embodying the invention is embodied in a highpotential insulating bushing comprising an upper insulating section 10which is provided with eX ternal insulating-capes 12, a lowerexternallycorrugated insulating shell 14, and an intermediate metal connectingsleeve 16 of somewhat larger diameter than said shells which comprisesthe support for said upper and lower insulating shells and 'also for thebusha port for a packing ring 32 -on which the lower end of saidinsulating shell rests and outwardly beyond said collar to provide arover for the open upper end of said sleeve.

Bolts 34 extend through said 'flange 30 and an I upper outstandingflange 36 of said sleeve j which latter flange isv adapted to supportthe insulator in the casing wall 38 of an electric switch ortransformer. Suitable packing-40 is finterposed between the confront eing faces of said'anges 30 and 36 whereby to provide`a breakable fluidtight joint thereat. A tubular current conducting stud 42 is `extendedaxially through said lbushing and.v

beyond the ends thereof and is rigidly afixedat its lower end to thebottom of said lower insulating shell 14. To this end a tubular metalsleeve 44 is united with said stud at its lower end which is providedwith an upper flange 46 which overlies the bottom wall of said shell. Anouter metal ring` 48 is affixed to said sleeve beneath said shell wherebto secure the stud permanently in the bus ing at its lower end.l A metalcollar 50 is secured, as by cement, to `the upper end of said insulatingshell 12 and is provided with an outstanding attaching flange 52 onwhich`an oil reservoir is adapted to rest.

' Said reservoir includes an annular bottom plate 54 which rests uponsaid flange 52 and is secured thereto by bolts 56 having a centraltubular upstanding wall 58 which closely surrounds the stud 42 andprovides lateral support therefor at'its upper end. Radially outstandingwebs 60 connect said tube 58 and bottom plate 54 between which webspassages 62 are provided which are in communication with the open upperend of said insulating shell 10. An outer cylindrical housing 64 betweensaid insulating tube 72 16 of the bushing. (0

of glass is received in fluid tight manner in a groove 66 in' the uppersurface of said plate 54, and a cap 68'isprovided, through which saidstud extends' and ywhich. forms a cover for the open top of saidcylinder 64. Said ca 68 is provided with acentral upstanding tubularneck through which said stud eX- tends and a terminal cap 70 is aixed,as by screwLthreading, to the upper end'of said stud in surroundinrelation with said neck. Said stud-42 1s provided intermediate its endswith a tube of insulating'material 72 which may comprise a plurality oflayers of bakelized aperor other insulating material, and three aterallyspaced concentric insulating tubes 74, 76 and 78 are suitably supportedand the sleeve core path of-low reluctance. A secondary 92 is locatedwithin said-core strucwindin ture ad]acent the inner 4cylindrical plate84 thereof and a primary winding 94 is located between said seconda-rywinding and the out-l slde cylindrical core plate 86, and said windingsare spaced apart from'each other and from the core plates by meansof-the annular lnsulating spacers 96 whereby to insulate them from thecore structure and from each other. A body of oil 98 is providedjn theinterior of said bushing to a level intermediate the height of the glasseylinder 64 of va. high potential.

said reservoir-and is adapted to occupy the spaces between thetransformer primary and the adjacent parts of the transformer, thus toprovide a high degree of insulation for said.

inwardly through the ground sleeve for connection with the lowermost ofa plurality of reactance units .hereinafter to be described. At-leastone of the terminals of the secondary winding 92 is brought out throughthe side wall of said sleeve 16 to the insulated terminal 104 whichconstitutes thel low potential terminal of the bushing, the otherterminal of said secondary winding preferably being grounded tothesleeve 16.

In accordance with this invention the electromagnetic transformer abovedescribed is designed to -be energizedJ at a potential considerably'lower than the potentialsof the bushing terminal 70, since it is notdesirable to insulate the primary winding 94 for such Accordingly aplurality ofserially connected reactance units are' provided within theupper insulating shell lalong the length thereof which are included inseries with the primary winding of said transformer between the groundedsleeve 16 and the high tension terminal 70 of the bushing. Said units,as shownl most clearly in Fig. 3, comprise the multi-turn windings 106,carried by the inner tube '7 2 andsimilar windings 108, 11'0 and 112which are supported in vertically spaced relation on and are insulatedbyl said intermediate tubes 74, 76 and 78 respectively, the adjacentterminals of said ywindings being electrically connected by means ofconductors 114, whereby to connect all of sald4 windings electrically inseries. The lead 114 of said lowermost reactance unit 112 iselectrically connected with the u`n-.

l'be insulated for only a small part of the total voltage of the hightension line connected with the bushing. The. several reactance umts maybe designed to divide the voltage drop equally therebetween or where itis desired the up vermost reactance units may be wound of a igher4resistance wire, whereby to assumeva greater proportion` of the drop. l

provide magnetic cores for the several reactance units.` Such aconstruction is shown in Fig. 4 in whicha pair of adjacent reactanceunits are separated by an annular U-shaped insulating ring 116 which isloosely received on the supporting insulating tube 74. Each winding isenclosed between inner and outer concentric insulating cylinders 118 and120, one of which, as the inner cylinder 118, has. a bottom portion 122which spaces apart said" cylinders.l Said cylinders 118 and are wrappedabout with strips of soft transformer steel 4124 whichconstitutes aclosed magnetic circuit about the winding and consequently considerablyincreases the reactance thereof. i*

In Figs-5, 6 and 7, the' invention is illustrated in connection with apotential transv former. As here shown the transformer comprises acylindrical base portion having. the upper and lower detachablyconnected sections 126 and 128 having the proximate outstanding annularanges 126e and 128e through which bolts 129 extend, and the uppertubular insulating shell 130- which is provided with the external ycapes 132. Said upper base portion 126 has an annular inwardly directedange 134 which carries a packing rin on which the lower endof saidinsulating shell- 132 is received and an upstanding cylindrical collar136 which is spaced apart from the lower end of said shell to receive abody .of cement 138 by which said shell is permanently secured to theba'se. Said shell isv also provided at its upper end with an annularcollar 140, which is perma-4 p nently' secured thereto by' cement -142vand which has an annular outstanding iiange 144 to which an oilreservoir is secured in fluid tight relation. Said reservoir comprisesupper and lower cylindrical metal plates 146 and 148 which aremaintained in-spaoed relation by a central upstanding tube 150 which isformed integral with said lower plate'and against the upper endof whichthe upper end of which the upper plate 146 is arrangev to bear. 'Acylindrical glass tube 152 constitutes the outer wall of said reservoir.Said upper and lower plates 146 and 148 are secured together by means ofperipherally arranged tie bolts 154which extend throughsaid upper andlower lates and the attaching y flange 144 of said she Said lowerplatei148 is formed with a plurality of passages 156 which are'disposedabout the central tube 150 thereof and provide for free iuidcommunication" between the interior portion of said f y has a dependingconducting stud portion 1630' 70 which projects downwardly into theinsulating shell of said bushing, whereby to more eltlrellly distributethestress at the top of the s e .i

An electromagnetic transformer 162 is located within the base portion126 and is supported removably therein on an annular i bracket 164which-is secured detachably `to the inner wall of said base portion bycap screws 166. Said transformer comprises a core frame 168, a primarywinding and a secondary winding 172, both of which windings are locatedon and suitably. insulated. from the upper leg of the core. Leads 17 4are brought outu from said secondary winding and extend through aninsulating bushing` 176 exteriorly of said base portion and constitutethe low tension terminals of the potential transformer. One lead 178 ofthe primary ;winding of said electromagneticvtransformer is connected toagrounded terminal 180 of said base andthe other lead 182 thereof isextended upwardly into the shell 130.-

A plurality of serially connected reactors 184 are disposed rwithin theinsulating-shell 130 along'thelength thereof.l Said reactors aresupported in superposed position in said -shell about a centralinsulating tube 186 which is secured at its bottom end by bolts 188 tothe tubular upstanding neck 190 of a circular plate 1 92. Said plate 192has an annular flange 194 which is secured bythe cap screws 195 to thellower face of the inwardly insulating spacing members 196 ofgendirected annular. flange 134 at 4the up er end-of said base portion126. Annu ar erally U-shaped section are interposed be- 'tween theseveral reactors fand serve to in- .sulate them one from the other. Thethree orted on a somewhat smaller insulating tube 198 which is suitablysupported by said .insulating tube 186. The lead 200 of the uppermostreactor unit 184 is connected electrically with the central upstandingtubular portion 150 of plate 148 and through the upper plate 146 withthe terminal 1 58. rl`he terminal 202 of said lowermost reactor unit isuppermost reactor units are similarly supno connected to the lead 182 ofsaid electromag- 3m .,actor units. 1t will be evident that the primarywinding 170v of the electromagneticl transformer is electricallyconnected in series with the reactors 184 between the high ten'- sionterminal 58 and the ground terminal 180. By suitably designing thereactance of the several reactors 184 the potential of the primarywinding 17 0 of the electromagnetictransformer can be of such value thatno, dillilicult problems of insulation are involved.

As shownin Figs. 5 and 6, the several reactors 184 are provided withmagnetic cores which substantially envelop the reactor windings althoughin some instances the core may be dispensed with orl as here shown maybe provided with an air gap. The cores herein shown comprise thegenerally annular bottom portion 204, which is substantially U-shaped incross section and is provided with a gap 205, between the upstandingU-shaped arms of which the reactance windings 184 are received, and anupper circular cover rportion 206 having a corresponding gap 207, whichis received on the upper ends of said U-shaped portion. As thus arrangedthe cores and the lnterposed insulating annular spacer members 196constitutea supporting column for the reactor units which are held inalignment by the inner insulating tubes 186 and Means arel also providedto supply the primaryl winding ofl the electromagnetic transformer witha leading exciting current, for the purpose of correcting the phaseangle displacement resulting-from the reactors 184.

Said means includes a frustro-conical insulating tube y208 having arelatively thick insulating wall in which a plurality of serial- .lyconnected parallel condensersare arranged i along the length thereof. Asshown most clearly in Fig. 7 each of said condensers comprises a pairoit concentric parallel plates a and an intermediate' overlapping plateb which is interposed between said outer plates a, the several plates ofthe condenser being supported and insulated from each other by thematerial of said tube. Each plate b is common to'two adjacent sets ofouter plates a and thereby constitutes means for connecting the adjacentparallel condensers in series. The uppermost set of parallel plates aare connected electrically with the lead 200 of the uppermost reactorunit and the lowermost intermediate plate b is electrically consulatingfluid, as oil, is adapted to occupy the casing to a level intermediate,the height of the reservoir at the top of the bushing, whereby tocompletely submerge the electromag- As thus arranged it willL netictransformer w1162, the reactors, and the condensers above described. Theinsulating tube 208 is provided with a series of peripherally arrangedpassages 214 adjacent the' lower end thereof which provide l for freecirculation of the. oil about the condenser tube 208. The oil is alsofree to circulate by thermal action labout ther electromagnetictransformer and reactor units.

The potential transformerabove described presents an inexpensive andreliable arrangement for deriving low'potential power from a hightension line to perform the operations heretofore requiring the use ofan expensive high potential electromagnetic potential transformeryand isfree from many of the 'diilicult problems present in the insulation ofsuch transformers.- It is also possible to greatly improve the phaseangle of the secondary low tension power by winding all or certain onesof the reactance coils 184 of suitable resistance Wire.'

In my concurrently tiled application Serial No. 499,142,\l havedescribed and claimed still another construction for obtaining thevoltage drop between the high tension terminal and the primary windingof the electromagnetic transformer, certain features of which aredisclosed in this application.

Various modications in the arrangement,

and construction ofkthe parts may be made without departing fromthescope of the invention. l

I claim:

1. A combined potential transformer and insulating bushing comprising anouter enclosing shell, a conducting stud extended through said shell,high tension terminals at the ends of said bushing, an axial insulatintubelocated within said shell, a plurality o reactance coils havingcentral passages through which saidltube extends surrounding and carriedby and' located invertically spaced relation along the length of saidtube, means electrically connecting said reactance coils in seriesbetween a high tension terminal of said bushin g and ground, and a lowtension lead extendedf exteriorly of said bushing deriving its powerfrom a selected one of said reactance coils.

2. In a potential transformer, the combination of an enclosing casingcomprising an upper insulating shell portion having a high p tensionterminal at the top and a lower metal supporting portion, a plurality ofreactance coils having aligned central passages arranged in superposedorder along the length of said shell portion, an axial-insulating-tubeextended through the passages in said coils and having a support at itslower endon said v base portion, means electrically. connecting saidreactance coils4 in series between said high tension terminal and metalsupport, a lowtension terminal extended through and insulatedpfrom Isaidmetal supporting portion, and means to supply power to said low tensionterminal from one of said reactance coils. j

3. In a potential transformer, the combination of an enclosing casingcomprising an upper insulating shell portion -and a lowermetalsupporting base portion, an electro- A magnetic transformer located insaid base ELO ings which are disposed about said tube in.

vertically spaced relation, annular insulatin spacer members alsodisposed about said tu between adjacent windings of said reactors, andmeans electrically connecting the 'windings of said reactors in serieswith the primary winding of said transformer, said secondary windinghaving oneof its leads exv,.in'inal.

tended exteriorly of said casing and constituting a low tension terminalof the potential n transformer.

4. In a potential trans-former, the combination of an enclosing casingcomprising an upper insulating shell portion having a high tensiontermina-l at the top and a lower metalv base portion, an electromagnetictransformer located in said base portion having'primary and secondarywindings, an inner insulating tube concentricwith said shell portion andspaced apart from the side walls thereof having a support at'the lowerend on said base portion, a plurality of annular reactors located onsaid insulating tube along the length thereof, said reactors having thewindings thereof electrically connected in series with each other andwith the primarywinding of said transformer, the free terminal of saidtransformer primary having a grounded connection with said base and thefree terminal of said uppermost reactor having an electrical connectionwith said 5. In a potential transformer, the combination of an enclosingcasing comprising a lowerl base portion and an upper linsulating portionhavlng a high tension terminal at the top, an inner insulating tubelocated within and spaced apart from the side walls of said insulatingshell'and having a supportvat its lower end on 'said base portion and aplurality of superposed reactors carried by said -insulating tube alongthe length thereof having windings which are electrically connected inseries,- nieans to connect the winding of said uppermost reactorelectrically with said high tension terminal and the j winding of saidlowermost reactor'with said f base, and a low tension lead extendedexteriorly of said casing and having a power-transmitting connectionwith said connected reactors adjacent the 4base end thereof.

high tension ter- 6, a potential transformer, the combination of a iiuidtightenclosingcasing comprising a lower grounded base portion and anupper insulating portion having a high tension terminal at the top, aninsulating tube vo y.

extended through said insulating shell, a p lurality of annular reactorunits surrounding said tube and supported thereby in spaced relationfrom said shell, annular insulating spacin members surrounding said tubedisposed etween adjacent reactor units, and" means electricallyconnecting the windings of said reactors electrically in series betweenaid high tension terminal and said grounded ase.

7. In a potential transformer, the combi` 4terminalat the top of saidshell portion, an insulating tube extended within said shell portion, a;plurality of reactors carried by A said tube in superposed relation andsupported by said tube in spaced relation with sa1 d outer casing, eachof said reactors comprising an annular core member through which saidinsulating tube extends and an annular winding associated with said coremember, annular insulating members surrounding. said insulating tube anddisposed between adjacent lreactor units, and meanselectricallyconnecting the windings of said reactors electrically in series betweensaid high tension l terminal' and said grounded support.

8: In apotential transformer, the combination of an outer tubularenclosing casing comprising a lower grounded support and an upperinsulating shell having a high tension terminal at the top thereof, acolumn of superposed annular reactors located within said casing,annular insulating spacer members located between adjacentreactor units,and an axial insulating and supporting tube extended through saidannular reactor units and spacer members arranged to sup ort them in'spaced relation`from the side wal s of said enclosing casing, saidreactor units arranged to be electrically connected in 'series betweensaid high 'tension terminal and said grounded support.

l9. In 'a' 4potential transformer, the com-v. bination of an outertubular enclosing casing comprising a lower grounded portion andan upperinsulating shell portion,a high tension terminall at the top of lsaidshell portion, a

llo

iis YJ low vtension terminal carried by and insulated I I from `saidgrounded portion, a central insusulating spacer `members alsosurrounding said tube and interposed between adjacent reactor units,each of said reactor units comprising an annular core member having awinding thereon, means electrically connecting the windings of adjacentreactor units in series, a second insulating tube located withinsaidshell surrounding said reactor and having metal condenser insertsembedded in and insulated from each other by the material of the tube,and means electrically connecting the -condensers of said tube inshunting relation with said reactor windings.

` 10. In a potentialtransformer, the combination of an outer enclosingcasing comprisinga lower metal base portion and an upper insulatingshell having a high tension terminal at the top thereof, a centralcolumn of superposed reactance coils located within said casing havingan axial passage therethrough, an axial insulating tube extended throughsaid 'passage having a support at one end, whereb to support said coilsin spaced centric and overlapping metal plates em-l bedded in andinsulated from each other by` bushing, an

relation wit the side walls of said casing, asecond tube of insulatingmaterial located within said casing and surrounding said column ofreactance coils having spaced conthe insulation of the tube comprising aseries of vertically arranged condensers, and means electricallyconnecting said condensers inshunting relation with said reactancecoils.

11. A high tension bushing comprising upper and lower insulatingshellsand an intermediate connecting ground sleeve, high tension terminals atthe remote ends of said shells, a low tension terminal carried by andinsulated from said ground sleeve, a conducting stud extended throughsaid shells and sleeve, an electromagnetic transformer located in saidsleeve surrounding and insulated from vsaid stud having a primarywinding, one terminal -of which is grounded on said sleeve, and asecondary winding, one terminal of which is connected with said lowtension terminal, an insulating tube extended in said upper insulatingshell between said transformer and the upper high tension terminal, anda plurality of serially connected reactance windings carried by saidtube and electrically connected in series with said primary windingbetween said upper high tension terminal and the free terminal of saidtransformer primary.

12. The combination with a bushing insulator having a grounded support,of a conductor extendedthrough said insulator, high tension terminals atthe ends of said insulator, an annular magnetic core member disposedwithinsaid insulator about said conductor, a magnetizing winding forsaid core member, a low tension winding located in the field of saidcore member having low tensioned terminals extended exteriorly of saidaxial insulating tube surrounding 18. The combination with an insulatingbushing'having upper and lower insulating shell portions and an enlargedvintermediate metal connecting portion, of an electromagnetictransformer located in said enlarged portion having a central passagetherethrough, said transformer having a high tension primary and a lowtension secondary winding, a stud extended through said bushing, hightension terminals at the ends of said bushing, an insulating tubesurrounding said stud, and a plurality. of reactance windings carried bysaid tube and electrically connected in series with the primaryr windingof said transformer between a high tension terminal of said bushing andground,

`said transformer secondary winding having a low tension lead thereofextended exteriorly of said bushing.

14. An insulating bushing having the combination of upper and lowerinsulating shells, an intermediate metal connecting sleeve, an axialstud extended through said bushing,

Vhigh tension terminals at the ends of said bushing, an insulating tubesurrounding said stud, an annular magnetic core surrounding said tube inthe vicinity of saidl sleeve, primarily and secondary windingsassociated with said core, said primary winding having one lead groundedon said sleeve, and said seeondary winding having a low tension leadextended exteriorly of said bushing, a plurality of vertically spacedreactance coils carried by said insulating tube along the length thereofhaving their coils electrically connected inseries, and meanselectricallyr connecting the uppermost reactance coil with a hightension terminal of said bushing and the lowermost coil with the otherlead of said primary winding. 1

15. An insulating bushing having the combinati on of upper and lowerinsulating shells,

an intermediate metal connecting "sleeve, an axial stud extended throughsaid bushing,

high tension terminals at the ends of said bushing, an insulating tubesurrounding said stud, an annular magnetlc core surrounding said tube inthe vicinity of said sleeve, ,pri-

vhigh tension terminal of said bushingl and fthe lowermost coil with theother lead of said primary winding, certain of said reactance coilshaving their windings composed of a high resistance material whereby f*to correct the displacement in the phase angle of said low tensionsecondary.

16. An linsulating bushing having the combination of upper and lowerinsulating shells, n an intermediate metal connecting sleeve, an axialstud extended through said bushing, high tension terminals at the endsof said insulating shells, a low tension terminal carried by andinsulated from said sleeve, a plurality of spaced concentric insulatingtubes surrounding said stud, a` plurality of reactance coils carried bysaid tubes and arranged in superposed order along the length of saidupper shell, the uppermost of said coils having the turns thereofcomposed of high re-l sistance wire, means electrically connecting saidreactance coils in series between a high tension terminal of saidbushing and said sleeve, and a winding inductively connected with one ofsaid coils having a connection with said low tension terminalu Intestimony whereof, I have signed my name to this specification.

GUSTAV E. JANSSON.

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